Liquid discharge device and cleaning method for liquid discharge head

Abstract

A liquid discharge device includes a liquid discharge head including a discharge port surface on which discharge ports for discharging liquid are formed, an electrothermal conversion element configured to generate energy for discharging liquid from the discharge ports, and a protection film configured to cover at least the electrothermal conversion element, and a cap configured to cover the discharge port surface, wherein the cap is arranged along the discharge port surface at a position opposite to the protection film via the discharge ports in a state where the cap covers the discharge port surface, and wherein the cap includes an electrode configured to be used to apply voltage between the protection film and the electrode.

What is claimed is: 
     
       1. A liquid discharge device comprising:
 a liquid discharge head including a discharge port surface on which discharge ports for discharging liquid are formed, an electrothermal conversion element configured to generate energy for discharging liquid from the discharge ports, and a protection film configured to cover at least the electrothermal conversion element; and 
 a cap configured to cover the discharge port surface, wherein the cap is arranged along the discharge port surface at a position opposite to the protection film via the discharge ports in a state where the cap covers the discharge port surface, and wherein the cap includes an electrode configured to be used to apply voltage between the protection film and the electrode, 
 wherein the liquid discharge device applies voltage between the protection film and the electrode to cause the protection film to be eluted into the liquid in a state where the discharge port surface is covered by the cap and electrical conduction is made between the protection film and the electrode via the liquid. 
 
     
     
       2. The liquid discharge device according to  claim 1 , wherein the protection film contains at least one of iridium and ruthenium. 
     
     
       3. The liquid discharge device according to  claim 1 , wherein the protection film contains a metal that is eluted by an electrochemical reaction with liquid. 
     
     
       4. The liquid discharge device according to  claim 1 , wherein the liquid discharge head includes an insulation film between the electrothermal conversion element and the protection film. 
     
     
       5. The liquid discharge device according to  claim 1 , wherein the cap includes a porous absorber inside the cap, and the electrode is provided on a surface of the absorber facing the discharge port surface in a state where the cap covers the discharge port surface. 
     
     
       6. The liquid discharge device according to  claim 1 , wherein the cap includes a conductive porous absorber inside the cap as the electrode. 
     
     
       7. The liquid discharge device according to  claim 1 , wherein the cap includes an elastic body that generates elastic force for allowing the electrode to urge the discharge port surface in a state where the cap covers the discharge port surface. 
     
     
       8. The liquid discharge device according to  claim 1 , further comprising a voltage application unit configured to apply a voltage between the protection film and the electrode. 
     
     
       9. The liquid discharge device according to  claim 1 , further comprising a suction unit configured to suction liquid from the liquid discharge head via the cap. 
     
     
       10. A cleaning method for the liquid discharge head of the liquid discharge device according to  claim 1 , the cleaning method comprising applying voltage between the protection film and the electrode to cause the protection film to be eluted into the liquid in a state where the discharge port surface is covered by the cap and electrical conduction is made between the protection film and the electrode via the liquid. 
     
     
       11. The cleaning method for the liquid discharge head according to  claim 10 , the cleaning method further comprising suctioning the liquid from the liquid discharge head via the cap to make electrical conduction between the protection film and the electrode via the liquid. 
     
     
       12. The cleaning method for the liquid discharge head according to  claim 10 , the cleaning method further comprising suctioning the liquid from the liquid discharge head via the cap, and discharging the liquid, containing the eluted protection film, from the liquid discharge head. 
     
     
       13. The cleaning method for the liquid discharge head according to  claim 12 , the cleaning method further comprising discharging the liquid, containing the eluted protection film, while applying voltage between the protection film and the electrode. 
     
     
       14. The cleaning method for the liquid discharge head according to  claim 10 , the cleaning method further comprising applying voltage while inverting polarities of the protection film and the electrode.